Artificial refrigerating apparatus



June 19, 1928.

1,674,162 J. H. DENNEDY A A ARTIFICIAL REFRIGERATING APPARATUSFiled,Aug. 18- 1921 :5 Sheet t 1 A TTORNEY.

June 19, 1928,

J. H. DENNEDY ARTIFICIAL REFRIGERATING APPARATUS Filed Aug. 18, 1921 1 5Sheets-Sheet 2 INVENTOR.

g BY A TTORNE Y.

June 19, 1928;

J. H. DENNEDY ARTIFICIAL REFRIGERATING APPARATUS Filed Aug. 18, 1921 5Sheets-Sheet INVENTOR.

ATTORNEY. v

Patented June 19, 1928.

UNITED STATES 'PATE JAHESH. IJZEI'TN'EDY, OI DETROIT,

MICHIGAN, ASSIGNOB, SERVEL, me; or NEW xonx, N. Y., A CORPORATION or DLAWARE.

NT oar-"Ice;

BY MESNE ASSIGNMENTS, 1'0

ARTIFICIAL REFRIGERATING APPKBATUS.

Application med August 18, 1921. Serial No. 493,260.

. This invention relates to artificial refrigerating systems, and anobject of the invention is to provide a compact and efliciently sureline, and the principal feature of construction of this invention is inthe provision of a brine-circulating system including a. series of coilslocated in a chamber forming part of the expansion system or lowpressure side of the apparatus. The brine is cooled in this expansionchamber and circulated through a conduit leading to and from the chamberor insulated room to be cooled. In previoussystems the expansion coilsof the system have often been placed in a brine tank to reduce thetemperature of the brine therein, which tank is located in the chamberor room to be cooled. With my system the brine is circulated through 5 acoil in a closedcircuit to and fromthe chamber or room to be cooled andthis brine coil is placed in the refrigerant ina chamber, under thepressure of the expansion s de of the system. By this arrangement Isecure not only a more effective cooling of the brine but am able toprovide a system for use for instance in apartment houses where thereare a series of refrigerators to be cooled in which case therefrigerating apparatus may be placed at any convenient point and thebrine cooled in the apparatus and transferred through the entire seriesof compartments or chambers to be cooled and returned "to the apparatuswhere the heatabsorbed by the brine is taken up by the re-.

frigerant. Other features of thenvention reside in the construction ofthe expansion chamber containing the brine coils and mechanism fortransferring the refrigerant from. the high pressure line to thischamber, and in means actuated b variation in pressure of the expansionside of the system for. starting and stopping operation thereof. Theseand other objects and various novel features of my invention arehereinafter more fully described and claimed, and the preferred form ofapparatus embodying my The system includes a .4 leads from the dischargeend the compressor 13. The valve 8 invention is shown in drawings inwhich- Fig. 1 is a vertical section partly in -elevation of my improvedartificial refrigeratlng apparatus. I a

1g. 2 1s a plan view thereof. v i

Fig. 3 is a detail in section showing the valve between the high and lowpressure side of the system. q Fig. 4 is a detail of a presure actuatedswitch for controlling operation of the motor.

I prefer to arrange the device in compact form as shown in theaccompanying drawings and for the purpose I provide a. base 1 havin atone end a hollow chamber 2 above w ich is mounted a compressor 3 Whichmay be of. any approved type, here shown as being of the twocylinder'type having an the fluid is transferredv from the low pressuresideof the system., A discharge line of thecompressor through adischarge line 4 to the coils 5 in the cooling chamber 2 forming .a partof the high pressure side of the system. The discharge line 4 leads froma valve housing 8, which is formed in the top of assageway from afilling pipe 8 intothe igh pressure side of the system. The shank 8 ofthe valves?v is threaded in the valve housing 8 so that by applying acloses aintake chamber 3 into which the accompanying normally wrench tothe squared outeren'd of the stem,

the valve head may be moved off its seat and, if desired, may be removedfar enough to seat against the opening tothe discharge line 4, so that.refrigerant from a suitable supply maybe admitted through the .pipe

8 to replenish the supply without lowering the. pressure in the.condenser coils. The

pump or compressor is operated by means of a motor-mounted on the samebase having a shaft coupled by means of a coupling 7 to a v gear trainin the case 10. Thegears are not as being connected of the compressor.

On this same base and atone side ofthe being here shown but are to beunderstood with the crank shaft 11,: 1 i

compressor I mount what I have termed the' expansion or evaporatingchamber 12 above which is a chamber 13 connected with the .switch tostartand operation of the coils 5 by means of a conduit 14. This chamber13 and conduit 14, coils 5 and line 4 provide the high pressure side ofthe system. The fluid compressed and discharged into the line 4 isheated by such compression and this heat plus the heat absorbed in theevaporating chamber is removed in the chamber 2 where the coils areimmersed preferably in water circulated through the chamber 2 in anyapproved way as will be readily understood. This condensed refri erantdischarges into the chamber 13, w 'ch has a discharge outlet controlledby the needle valve 16, which is operated b 'a float 17 therein. Thevolume of liquid 1n the chamber 13 controls the opening and closing ofthe valve and a detail of the valve is shown in Fig. 3 from which itwill be understood that, as the liquid rises above a certain level, thevalve is opened permitting discharge of fluid into the evaporatingchamber 12 there-- below and as the fluid in the chamber falls below acertain level the valve is closed. By this arrangement I am able tomaintain a practicall constant volume of refrigerant in the chem r 12.

The low pressure side of the system includes the chamber 12 and theconduit 18 leading to the intake chamber 3 of the comressor. There istherefore a closed circuatin system for the refrigerant which may methylchloride, sulphur dioxide or other well known refrigerant.

The brine circulating stem consists of a coil of thin walled tubing 19located in the evaporating chamber 12. This brine may be a salt brine oralcohol or other brine of the desired character and the brine coil isconnected by means of a pipe 20 with the circulating pump 21 which isconnected by meaps of a coupling member 22 with a s aft actuated by t egear train heretofore mentioned or an elongation of the shaft 11 of thecompressor as will be understood from Fi 1. From this pump, 21 the brineis trans erred through the pipe 23 to the compartment to be cooled andreturned by means of the pipe 24 to the coil 19. The chamber 12 ispractically, oval in form as will be understood from Fig. 1 and coils 19may be arranged therein in any ap roved manner and these coils areractical y immersed in the refrigprant in t e evaporatin chamber 12where t e brine is cooled. Pre erably the tubes or pipes 20, 23 and 24are insulated wherever exposed to atmosphere as is sometimes the case intransferring the fluid to some little distance from the apparatus. Thisis likewise true particularly with the line 18 of the low pressure sideof the system.

It isusual in artificial refrigerating stems to use a thermostaticallycontrol ed paratus by variation in temperature of of which, as ishereinafter described, I

am able to hold the brine at a practically constant temperature. Thisressure controlled switch is indicated in Fig. 4 and consists of a casin40 connected by means of a pipe 41 with the low pressure line 18 of thesystem. Within this chamber is a circularly corrugated expansible member42 and the chamber 40 is formed between the exterior of this member 42and the outer casing 43. This cylinder 42 is closed at the bottom b aplate 44 and the upper end is connecte to a member 45 so that thechamber 40 is sealed with the exception of the opening of the pipe 41.The member 45 is held between the casing 43 and the cap 46 which has acentral aperture, practically e ual in diameter to the interior diameter,0 the member 42, which is threaded to receive the adjustin member 47.Between this adjusting mem er and the plate 44 is a coiled spring 48tending to hold the member 42 in expanded condition. Connected to thisbottom plate is a stem 49 extending u ward through the central aperturein the a justing member 47 to a switch mechanism 50 having a blade 51which may be operated by longitudinal movement of the lunger tc make andbreak contact with t e contact unembers 52 of the current supply lines53 for the motor. On an excess of pressure in the line 18 the springiscompresse'd and the plun er moved upward to close the switch whicstarts the motor to operate, and operation of the pump or compressorwithdraws the fluid from and reduces the pressure in the line 18' whichcauses the contact to be broken by expansion of the spring 48. Thus on acertain reduction of pressure in the expansion line the apparatus isstopped and on an increase of pressure in the expansion line theapparatus is started in operation. The adjustments provided for enablethe switch control device to operate at the desired high and lowpressureand thus predetermine the tem rature of the body being cooled which, int is case, is the brine. By varying the tension of the spring 48, and byuse of the other adjustments, the system may be made to operate with apressure controlled switch to %lit6 closely control the temperature 7 oft e compartment being cooled by-the brine system.

The operation of the system will be understood from the followingdescription: Let it be assumed that it is desired to maintain the brinesystem at a temperature rangin from twenty-five to thirty degrees F.,and

let it 7 a refrigerant. The

be assumed that sulphur dioxide used as upon theparticular refrigerantused. The amountof'heat passed through any conductor in a unit of timemay be expressed by the equation Q=AX (T''T) XC in which Q equals thequantity of heat transmitted in a unit of time and therefore is the rateof flow of heat through the conductor. A equals the effective area ofthe conductor through which the heat will pass. T equals the temperatureof the source of heatthat is, in this instance the temperature of thebrine body to be cooled. T equals the temperature of the medium whichabsorbs or takes up heat from the warmer bodies and in this case is thetemperature of the boiling refrigerant. C equals the coeflicient whichbecomes a constant for similar conditions.

In any refrigerating system with the compressor running at a constantspeed, Q is practically a constant quantity when variation in theevaporating pressure is not. great. A is also a constant when a floatvalve is introduced as shown herein to control the flow of condensedrefrigerant from the chamber 13 into the evaporating chamber 12. C isconstant for any type of system when conditions are similar andtherefore the quantity T T must also be a constant and in this instancelet it be assumed that TT" isten degrees F., while the system is inoperation. Let it also be assumed for our present purpose that the brinebody being cooled has reached maximum temperature of thirty degrees F.,and that the compressor has been running for several minutes. If, as haslqeen assumed, it requires ten degrees diiferen e of temperature toforce the heat through the available area at the required rate then thetemperature of the refrigeratmg medium must be twenty degrees F. andwith sulphur dioxide, the pressure in the evaporating system must be twoand onehalf pounds per-square inch gauge pressure.

As the machine continues to operate and heat is absorbed from the brinethe temperatureof the brine body falls and as the temperature falls tothe minimum of twentyfive degrees F., the temperature of the boilingliquid in the evaporating system must be fifteen degrees F., and theevaporator is now under one-half pound gauge pressure per square inch.Under this reduced pressure the switch 51 is opened stopping operationof the motor and compressor. As the brine reaches twenty-five degreestemperature and the temperature of the liquid in the evaporator 12 isfifteen degreesF.. heat will continue to flow, because of thisdifferencein temperature, from the source of heat (which is the coils19) into the liquid reprinciple of p o eration, however, would apply toany re rigerant but the numericalequation would dependsion line 18mounted over the chamber,

frigerant which will be evaporated intoa gas. Inasmuch as the compressoris stopped at the time of this addition of heat to the liquidrefrigerant, this evaporation will cause an increase of pressure in the[expanand when this pressure reaches about 4.6 pounds per square inchgaugepress' sure, evaporation will cea e because the tem-', perature ofevaporation of sulphur'dioxide at 4.6 pounds auge pressure istwenty-five degrees F., which is the temperature of the source of heatand therefore heat ceases to. flow through the conductor.

Under the conditions above set forth, whenv the brine has reached atemperature of thirty degrees F., the liquid refrigerant has alsoreached. the same degree of temperature. This being so, the pressure inthe evaporating coils is now about seven pounds per square inch gaugepressure'which will close the switch and start the motor. The starting.and stopping of the apparatus is thus controlled by a variation inpressure of the evaporating or low pres ure side of the system as statedheretofore and the advantage of thus controlling the starting andstopping is that, while the brine is maintained within a five degreerange of temperature, there is available a difference of pressure of sixand one-half pounds per square inch for actuating the control switch.With a thermostatically controlled switch the starting and stopping ofthe mechanism would be through a range of 2.4 pounds pressure per squareinch because the pressure corresponding to a temperature of thirtydegrees F., is seven pounds and presssure corresponding to twenty-fivedegrees F., is 4.6 pounds per square inch gauge pressure. By introducingthis starting and stopping device in the suction or low pressure line arelative large difference of pressure is made available with a relativesmall variation in the range of temperature.

From the foregoing it becomes evident that the system is entirelyautomatic in operation; is compact in form and highly efficient inoperation. During the periods of operation of the apparatus the liquidrefrigerant is automatically transferred from the high to low pressureside practically as fast as it accumulates and a practically constantmaximum quantity of refrigerant is maintained in the evaporating chamberwhich is the condition under which the mo t eflicient result isattained.

Having thus described my invention, what I claim and desire to secur entof the United States is In an artificial refrigerating apparatus, a basehaving a cooling chamber, a compressor a circulating system forrefrigerant having a high pressure side including a series of coils inthe said cooling chamber, a double compartment e by Letters Patchamberalso mounted on the'b'ase, one compartment being open to the highpressure side of the system and the other compartment being open to thelow pressure side of the system, a float controlled valve forcontrolling the discharge of the liquefied refrigerant from the highpressure to the low pressure chamber into the top of the low pressurechamber, a brine circulating system including a series of coils locatedin the said low pressure chamber, a pump for circulating the brine inthe system therefor, said pump being connected with the compressorshaft.

In testimony whereof, I sign this specificat-ion.

JAMES H. DENNEDY.

